A conventional agricultural combine includes a header assembly for severing and collecting crop materials as the combine is driven through a field and a feeder mechanism for advancing and elevating the crop materials to a threshing area on the combine. In the threshing area of the combine, the crop materials are threshed by a rotor assembly to separate grain from material other than grain.
A typical rotor assembly includes an elongated cylindrical member or rotor having a series of threshing elements peripherally arranged thereabout. The threshing elements outer surface is arranged proximate to and cooperate with a cylindrical casing which surrounds the rotor. The rotor is mounted on a frame of the combine and is rotatably driven at variable speeds depending on the crop material being harvested. As the rotor rotates, the threshing elements impact with the crop materials and thereby separate grain from material other than grain.
It is customary to use different rotors for harvesting different crop materials. For example, certain threshing elements having predetermined configurations will be peripherally arranged about the circumference of the rotor in a particular or preset manner when the combine is to be used to harvest small grain, corn and soybeans. On the other hand, certain other threshing elements having predetermined configurations and which are otherwise arranged about the rotor are used when the combine is used to harvest rice, edible beans and damp, weedy crops. As will be appreciated by those skilled in the art, use of a particular rotor configuration, which may be mismatched to the particular crop being harvested, can result in both inefficient waste of the primary crop, frequent jamming of the rotor, and downtime for the entire combine.
Combines are, of course, rather massive and relatively expensive pieces of agricultural equipment. Although the rotor is a relatively expensive component of the combine, some users find it advantageous to have numerous rotors on hand thereby enhancing versatility of the combine by changing the rotor for different crops. The rotor of a combine, however, is quite heavy and unwieldy, weighing far in excess of what is manually liftable even by several persons. Thus, and assuming that a number of different rotors are at hand, changing of one rotor for another in a given combine is a difficult operation, requiting the use of auxiliary lifting devices. Frequently, the practical effect of this situation is to severely limit the harvesting applications for which a combine can be used.
Some rotors are designed with a plurality of mounting lugs secured about an outer cylindrical wall of the rotor. Typically, these lugs are welded to the outer wall of the rotor to provide an array of helical rows, circumferential rows, and longitudinal rows over the entire surface of the rotor drum or wall. Threshing elements are releasably secured to the mounting lugs in predetermined order to accomplish the desired threshing effect for a particular rotor. The threshing elements are commonly secured to the mounting lugs as with a releasable fastener assembly which passes through apertures in the threshing element.
In accordance with that discussed above and depending upon the particular threshing action required, different types of threshing elements may be secured to the various arrays of mounting lugs extending along and about the outer wall of the rotor. Moreover, and depending upon the particular threshing action desired, the threshing elements are releasably secured to the mounting lugs to provide different arrays extending about and along the length of the rotor.
In some forms, the threshing elements have an elongated or helical configuration. As such, one end of the threshing element is secured to one mounting lug while the other end of the threshing element is secured to another mounting lug. The spacing an arrangement of the mounting lugs about and along the rotor, of course, must correspond to the spacing of the apertures in the threshing elements to allow for interchangability of the threshing elements.
As the combine passes over the field, stones, rocks and other hard debris may often be picked up from the field. Notwithstanding the operator's carefulness and/or rock traps provided in the feeder assembly, these stones and rocks occasionally pass into the threshing area of the combine. As the rotor operates, these rocks and other hard debris impact with the threshing elements and mounting lugs. The impact forces against the threshing elements can affect the fastener assembly holding the thresher element to the mounting lug and can furthermore cause denting and severe harm to the mounting lugs and the outer cylindrical wall of the rotor. Denting of the threshing rotor may likewise effect the threshing action of the threshing elements connected to the displaced mounting lug. That is, denting of the rotor and/or mounting lugs will likely alter the position of the threshing elements relative to the inner surface of the casing thus effecting the efficiency of the rotor assembly. Moreover, harm to the mounting lugs can increase the difficulty and thus time required to fasten a threshing element thereto.
Besides denting of the rotor, the unused mounting lugs arranged about the periphery of the rotor provide a multitude of edges which impact against the crop materials as the materials pass through the threshing assembly--naturally resulting in some level of abrasive action which typically damages the crop material. As used herein, the term "damage" is meant to include splitting, cracking, nicking, scratching and/or marring of the harvested crop materials. As will be appreciated, damaged crop materials is an inferior grade of product which quickly spoils and, therefore, only a relatively small percentage is permitted by volume in those products intended for human consumption. Because only a relatively small percentage of damaged material is permitted in those products intended for human consumption such as corn, soybeans, kidney beans, peas and others, farmers are paid a premium price for crop materials having a relatively low damage content by volume at a collection station.
Thus, there is a need and a desire for a combine having a rotor which can be readily converted for a wide variety of harvesting applications as required without having to remove the rotor from the combine and while providing a minimal number of edges which can impact against the crop materials thereby limiting damage to the crop materials as they are threshed in the threshing area.